Generates strong random passwords

pass.rb

require "date"

dt = DateTime.now

base = ("a".."z").to_a + ("A".."Z").to_a + ("0".."9").to_a
blen = base.length

passlen = ARGV[0]
if passlen == "-"
  passlen = gets
end
if passlen == nil then
  fail "Passlen arg is not provided!"
end
if passlen[/\D+\n/]
  fail "Given data is not number!"
end
passlen = passlen.to_i
pass = ""

tfa = %w[%Y %C %y %m %d %e %j %H %k %I %l %M %S %L %:::z %u %w %G %g %V %U %W %s %Q %3N %6N %9N %12N].shuffle
passlen.times do |i|
  f = ""
  tfa = tfa.shuffle
  tfa.each do |o|
    f << o
  end
  seed = 
    dt.
    strftime(f).
    delete(": ").
    to_i
  rndbts = Random.new.bytes(128).bytes.sum ** 4096
  s = Random.new_seed + seed + i*i + rndbts
  s = s**128
  rnd = Random.new 
  pos = rnd.rand(0..(blen-1))
  pass << base[pos]
  sleep 0.01
end

(passlen.floor / 12).times do
  pass[(0..(passlen-1)).to_a.sample] = "_"
  pass[(0..(passlen-1)).to_a.sample] = "."
end

puts "#{pass}"